Chem Lab

3.Calculate the value of Keq for the reaction. Explain how you used the data to calculate Keq.

Fe3+ (aq) + SCN– (aq) ←→ FeSCN2+ (aq)

I 3 2 0

C -x -x +x

E 3-x 2-x x

[x]3-x[2-x]=6x10-3

x = 3.6 x 10-2

[0.036]3-0.036[2-0.036]= 6.18 x 10-3

Part 2: Le Chatelier

1.State Le Chatelier’s Principle.

The principle states that it is possible to determine the effect of chemicals on equilibrium when conditions change.

2.Consider the equilibrium below, for which the forward reaction is exothermic.

X2 (g) + O2 (g)  2XO (g)

Predict and explain the effect of making the following changes on this equilibrium

a.Adding more X2

This will make the reaction favor the right side to create more XO to fet back to equilibrium.

b.Adding more O2

This will make the reaction favor the right side to create more XO to fet back to equilibrium.

c.Increasing the pressure

Both sides have two moles and both are gasses so this will not greatly affect the rate of equilibrium.

d.Increasing the temperature

Both sides have two moles and both are gasses so this will not greatly affect the rate of equilibrium.

Conclusion:

For the equilibrium constant lab, our hypothesis was correct and we were able to determine the equilibrium constant using the absorbance of the mixture from the spectrometer. We were able to determine the constant to be 6.18 x 10-3. We were able to determine the unknown concentration of a given solution of SCN- using this process. There were discrepancies in our data when calculating the SCN- concentration and the result was off by 5.6 x 10-3. This error could have been the result of not measuring out the exact amount of needed chemicals for the solution, which would have caused a different concentration to form and read an incorrect absorbency on the spectrometer; not using clean test...